A question we often hear from customers is, “What is patina?” The term ‘patina’ refers to the blue-green layer that forms on the surface of copper over time, much like rust develops on iron. Unlike rust, however, patina actually preserves the copper, protecting it from the elements. This process occurs naturally but can also be man-made to ensure a uniform color.
Perhaps the most famous patinated landmark is the Statue of Liberty. The copper covering Lady Liberty is 3/32 of an inch (less than the thickness of two pennies) and has developed a beautiful, light green patina over the 131 years it has stood in New York Harbor. Gorgeous patinas can also be seen on the Canadian Parliament Buildings in Ottawa, the Peckham Library in London, and the NEMO Science Center in Amsterdam.
Perhaps the most famous patinated landmark is the Statue of Liberty. The copper covering Lady Liberty is 3/32 of an inch (less than the thickness of two pennies) and has developed a beautiful, light green patina over the 131 years it has stood in New York Harbor. Gorgeous patinas can also be seen on the Canadian Parliament Buildings in Ottawa, the Peckham Library in London, and the NEMO Science Center in Amsterdam.
What Determines the Color of the Patina?
The ultimate color of the patina is determined by the corrosive elements it is exposed to. For example, continued exposure to sulfurs and oxides creates copper sulphate, which has a distinctive blue color. In saltwater environments, the patina may contain copper chloride, which is green. Before it takes on these colors, however, the copper will change from its original golden red to gradually darker shades of brown.
When Will Patina Develop?
The development and ultimate color of patina is determined by several variables, including temperature, humidity and precipitation, length of exposure, chemical environment, and the surface condition of the copper. However, environments generally produce patina in a predictable manner:
- Salt water environments: 7-9 years
- Industrial environments: 5-8 years
- Urban environments: 10-14 years
- Clean environments: up to 30 years
Can I Prevent Patina?
Except for controlled environments, there is no way to prevent the development of patina. Since cupolas and weathervanes are exposed to the elements, they will develop patina over time. However, if you are worried that you will not like the resulting patina, you can choose to have us patina the copper for you. This will ensure an even, uniform color on the copper.
For Beautiful Copper Call Valley Forge Cupola and Weathervanes
Our cupolas, weathervanes, mailboxes and lampposts all use durable, 24-gauge copper. Whether you choose a shiny or patina finish, the copper will withstand the elements for decades to come. If you’re not sure which finish to choose, we offer FREE digital quotes so that you can picture exactly how your cupola will look on your roof. Our cupolas specialists are always available to answer your questions and choose the right product for your home. Call us today at 866-400-1776 to learn more about our American-made cupolas!
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